Exploring the Uses and Mechanisms of Carbon Dioxide Fire Extinguishers

Carbon dioxide (CO²) fire extinguishers are essential for combating specific types of fires. Known for their effectiveness in handling electrical and flammable liquid fires, these fire extinguishers leverage the properties of carbon dioxide to smother flames carefully and effectively.

Our blog will delve into the various uses and underlying mechanisms of carbon dioxide fire extinguishers, providing valuable insights for homeowners, business owners and those interested in fire safety.

Discover how these extinguishers work, when to use them, and why they are critical in any fire safety strategy.

What is a Carbon Dioxide Extinguisher?

CO² extinguishers are invaluable for putting out electrical and Class B fires. As the name suggests, a carbon dioxide extinguisher is filled with - you guessed it, carbon dioxide. This pressurised gas is then used to smother a fire.

How do CO² Extinguishers Work?

Carbon dioxide extinguishers discharge CO². The gas is stored within the canister as a liquid and is created under pressure when the extinguisher's handle is squeezed.

When released, carbon dioxide expands rapidly, displacing oxygen in the air around the fire. This smothers the flames, as fire needs oxygen, an essential part of the fire triangle, to continue to burn.

How to Use a Carbon Dioxide Extinguisher

Only tackle small fires with an extinguisher. If the fire spreads rapidly, you must immediately evacuate the building and call emergency services. It is essential to avoid using CO² extinguishers in small rooms, as CO² gas is poisonous at a 4% concentration and can kill at just 8%.

To extinguish an electrical or class B fire, make sure you follow the below instructions:
  1. 1.Pull out the safety pin to break the anti-tamper seal
  2. 2.Squeeze the lever to start discharging the gas
  3. 3.Aim the extinguisher:

Class B Fires - The canister must be directed at the base of the fire and gradually moved along the entire area of the flames.

Electrical Equipment—First, switch off the power supply to prevent re-ignition, then direct the canister straight at the fire.

  1. 4.Ensure the fire has been completely extinguished. Reignition is possible when a CO² extinguisher has been used as the gas tends to drift off after use, and if the fire is still hot, it can just reignite.

What is a CO² Fire Extinguisher Used For?

CO² fire extinguishers should be used to smother fires from delicate electrical equipment such as computers or generators and fires involving flammable liquids, such as petrol, diesel, and paint, known as Class B fires.

This gas does not work by cooling the fire and is therefore not recommended for controlling Class A fires, including solids. This type of extinguisher must NOT be used on chip pan fires. This CO² will spray the burning out of the pan, and the fire will spread.

Benefits and Drawbacks of Carbon Dioxide Fire Extinguishers


  • This extinguisher can smother fires quickly in draught-free conditions
  • CO² is a non-conductor, so that it can be used on live electrical equipment safely
  • The gas leaves no residue and is not as damaging to electrical equipment as powder


  • CO² can be poisonous at a low concentration, so it should be used carefully when in confined spaces
  • CO² does not offer cooling properties and, therefore, can not prevent reigniting
  • The extinguisher is very loud, so the user must know this before use
  • A non-insulated horn can cause frostburn if the user touches it directly

Carbon Dioxide Fire Extinguisher FAQs

What is the purpose of a carbon dioxide fire extinguisher?

Carbon dioxide works by displacing oxygen as it is heavier than oxygen. This means it removes oxygen, one of the three elements of a fire triangle that stops the fire from burning. Carbon dioxide is very cold to cool the fuel, but it is not enough to prevent reignition, especially in a draughty environment.

Where are CO² extinguishers needed?

CO² fire extinguishers should be standard for premises with live electrical equipment, such as offices, shops, schools, and hospitals. Pairs of CO² and foam extinguishers are often recommended for these environments as they cover the vast majority of fire risks likely to be found.

What to do after extinguishing a fire with CO²?

Once you have extinguished a fire with CO², you should open all doors and windows to ventilate the room as the CO² removes the oxygen from the fire, but people need oxygen to breathe. It is essential to call firefighting services for larger fires and to check that smaller fires have been dealt with properly.

Explore CO² Fire Extinguishers with Fire & Safety Centre

Electrical and Class B fires can be easily handled with a CO² fire extinguisher. Fire protection is at the core of our business, so our team is committed to providing fire protection equipment that enables you to control and extinguish fires before they spread rapidly.

At the Fire and Safety Centre, we offer a range of fire safety and protection equipment, from fire extinguishers to fire alarms. Trust us to protect you in the event of a fire outbreak. Prepare for a sudden fire outbreak with our extensive range of products, and contact our team today to discuss your fire safety requirements.

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